When people say plot-no-jutsu to a question, theory, or suggestion, it means that the reason it didn't happen is because there's a plot. I believe that's what it means unless I missed something
it means something happened just for the sake of the plot
ex. sasuke didnt kill naruto because he had plot no jutsu on his side
These replies. It's the same thing with Talk-no-JutsuIts when Naruto is win because it will move on the plot or is important to the plot.
Like saying sasuke won against Danzo because it was essential to the plot to move on for sasuke to win, thus sasuke used plot no jutsu...